The steering in the all-new 2013  Mercedes-Benz GL three-row, seven-seat SUV feels light to the touch and  loose on center. This shortcoming is not attributable to any flaw in the  electrically assisted rack-and-pinion gear or lapse on the part of the  engineers who fret over chassis tuning. Instead, blame 50 clinic  participants—Southern Californians owning either a current Mercedes ute  or a competitive SUV—who drove GL prototypes and said that light and  loose is how steering should be.
  Shortly after it was introduced six years ago, the GL mounted the throne in the luxury-SUV castle with a C/D comparison-test win.  It not only impressed us with room and comfort, it scored high in  steering, handling, ride, and fun-to-drive categories. In two-plus-ton  trucks, such virtues are as rare as bud vases.
  Mercedes  resisted fiddling with the basic formula that made the original GL the  most popular large luxury SUV, even at the end of its six-year life  span. Changes to the outside dimensions, chassis layout, and exterior  design are modest. Thanks to more extensive use of aluminum (hood, front  fenders, suspension components), magnesium (dash support structure),  and reinforced plastic (engine mounts), curb-weight bloat is kept to a  minimal 50 pounds. All-wheel drive, an air-spring suspension,  French-stitched leather, and wood trim are standard. 
   
  To keep demanding customers in the fold and  to thwart competitors, Mercedes heaped in its best technology. Three new  engines—a 3.0-liter turbo-diesel V-6 and a pair of twin-turbo 4.7-liter  gas V-8s—bring more power and torque, quicker acceleration, and mileage  improved by 1 to 3 mpg. The enhanced seven-speed automatic now has  paddle shifters; instruments curious enough, in this application, to  suggest an attempt by Mercedes engineers to keep in some of what the  focus group took out. As an antidote to ever-thicker roof pillars,  there’s an optional camera system providing a bird’s-eye view of the  immediate surroundings. A new On/Off-Road package includes a low-range  transfer case, a center-diff lock, and ride-height adjustment. Optional  adaptive dampers and anti-roll bars check body motion. New available  safety aids forestall rear-end collisions, lane changes caused by  crosswinds, and nodding off at the wheel. For those who napped during  driver’s ed, automatic parking can be had. New electrical architecture  powers a 4.5-inch instrument-cluster display, a seven-inch center  screen, and a smarter COMAND infotainment system.
  An  ingenious second-row seat is the GL’s must-have option. The major  improvements over the previous generation are third-row access from both  sides and power operation. To provide easy entry, the rear doors are  long without feeling ungainly. Touch a button, and the second-row  backrest folds and a portion of the 60/40 split bench flips forward to  clear a path to the peanut gallery. When the mission is hauling freight  instead of a soccer team, the center row’s bottom cushions flip—followed  by the middle and rear backrests—yielding a nearly level load floor and  94 cubic feet of cargo space. Due to limited third-row kneeroom and a  second-row center-seat position equipped with a fold-down armrest/cup  holder, the GL is no seven-passenger limo, but it can nicely accommodate  four adults, three kids, and 16 cubic feet of luggage.
  The  three GL engines hum the same basic tune, raising their voices only in  response to jabs of the accelerator. All suffer from turbo lag. The  $63,305 GL350 welcomes newbies to the diesel fan club with smart  off-the-mark acceleration and 500-mile runs between fuel stops. Those  who tow boats and climb mountains would be wise to step up to the  $64,805 GL450; what its direct-injection V-8 loses in torque versus the  GL350’s diesel V-6, it more than makes up in power, rev range, and  passing acceleration (all three are rated to tow 7500 pounds). The  GL550, which starts at a hurtful $87,805, is the performance and  equipment king; adjustable dampers and 21-inch wheels and tires are  standard here.
  Tuning  the steering according to clinic results was a bad idea, but once a GL  exceeds around-town velocities, effort at the wheel builds and on-center  slack becomes less of an issue. During New Mexico test drives, we found  cruising comportment inversely proportional to tire/wheel diameter. The  19-inchers standard on the GL350 and GL450 require the least amount of  minding to maintain a straight path. Stepping up through the optional  20s and 21s, we noticed increasing amounts of ride jiggle and road  wander. Switching the adaptive dampers from “comfort” to “sport” also  diminished the GL’s ability to lock on to a straight path. Be advised.
  We  whined persistently about the previous GL’s squishy brakes. Pedal  travel remains longer than it should be, but once the slack is taken up,  there’s a firm feeling underfoot this time around.
  Mercedes-Benz’s grand luxe trump card arrives early next year: a GL63 AMG energized by a 550-hp, 5.5-liter twin-turbo V-8. Pray the clinic crowd never gets their paws on that one.
  Source: Caranddriver